U.S. patent application Ser. No. 099,953, entitled "System for High Resolution Exposure Address With Coarser Resolution Exposing Array", filed Sept. 23, 1987, by Agostinelli and Mir, describes advantageous imaging devices wherein an object source array (e.g. comprising a linear array of light valve elements) of relatively coarse resolution is imaged at a print zone in a manner providing a relatively higher resolution exposure. In one preferred embodiment, this approach utilizes (i) an object array having exposing pixels of width (W) located with intervening non-exposing spaces so as to have a center-to-center spacing S and (ii) a scan multiplexing optical system, e.g. including lens means and a mirror, which indexes the image of the exposing array in a number of increments, approximately S.div.W, to successive positions across a linear print zone. This system offers important advantages in simplifying array fabrication and in reducing electronic complexities.
The specific embodiments of the general multiplex approach that is described in the above-referenced application operate well in many exposing systems; however, we have found image artifacts to occur in certain systems employing that general approach. For example where the length of the exposing array is relatively large as a proportion of the array to scan mirror distance, undesirable exposure inaccuracies are visible at scan regions located near the ends of the linear scan zone.